Most diseases of the eye are treated with topical ophthalmic solutions containing pharmaceutical agents. It has been postulated that delivery and efficacy of these agents would be greatly increased if the agents were incorporated in ophthalmic lenses and those lenses were used as drug delivery devices. These agents may be added to the ophthalmic lenses by a variety of methods including soaking the agent into a formed lens, adding the agent to the formulation of the lens prior to its formation and the like. Despite the teachings of many, to date, there are no commercially available products for patients.
In order to gain approval for such a device, one must demonstrate the rate at which the pharmaceutical agent diffuses into and out of the ophthalmic lens. One of the possible reasons for the lack of commercial products is that current test methods to demonstrate dissolution rates of pharmaceutical agents through contact lenses are cumbersome. These methods rely on discrete sampling and are known to be labor intensive and expensive. In addition, these methods do not allow one to obtain continuous dissolution data. Therefore, it would be useful if devices and methods that to determine dissolution rates, and more particularly, continuous dissolution rates of pharmaceutical agents through ophthalmic lenses, would be useful. This need is met by the following invention